1. Field of the Invention
A commercial process for the production of epoxides comprises oxidizing an isoalkane such as isobutane to form a mixture of the corresponding hydroperoxide, e.g. tertiary butyl hydroperoxide, and alcohol, e.g. tertiary butanol, and contacting the mixture with an olefin in the presence of a suitable catalyst to form the epoxide. In the improvement of this invention, alcohol formed during the hydrocarbon peroxidation is replaced in whole or in part with an inert solvent such as decane prior to use of the hydroperoxide in the epoxidation reaction; substantial improvements in epoxidation reaction rate and selectivity are achieved.
2. Description of the Prior Art
The basic patent covering this technology is U.S. Pat. No. 3,351,635. This patent describes the reactants, reaction conditions, catalysts, and the like which are useful in the process. Although the patent describes the use of various solvents including hydrocarbons in the epoxidation most usually the components of the peroxidation reaction mixture comprised of the hydroperoxide and the corresponding alcohol are used directly in the epoxidation without the addition of extraneous solvents. See for example, U.S. Pat. No. 4,891,437 which emphasizes highly polar reaction mixtures and which requires high concentrations of hydroperoxide, the corresponding alcohol and product epoxide in the epoxidation reaction system.
R. A. Sheldon, Journal of Molecular Catalyses, 7, pages 107-126 (1980) "Synthetic and Mechanistic Aspects of Metal-Catalyzed Epoxidations with Hydroperoxides" teaches that polar solvents, particularly alcohols and water greatly retard the epoxidation and that auto-retardation by coproduct alcohol is observed.
An important consideration in carrying out the epoxidation reaction is the avoidance of high concentrations of hydroperoxide and the potential hazards associated therewith.